This invention relates to medical devices and particularly to an adapter which can be directly connected to a wide variety of catheters especially long term feeding and medicating catheters such as gastrostomy tubes, jejunal tubes, nasogastric tubes, or stomach tubes.
These types of catheters or feeding tubes as they are called, are needed to provide long term enteral nutrition to the patient. Typically, the patient can be fed by a choice of three methods of enteral nutrition: delivery by means of bolus feeding, pump feeding, or gravity feeding. Attached to the feeding tube is usually a connector with a plug cap or a flip cap which seals off the catheter when the patient is not being fed. The flip cap often comes off or leaks permitting loss of stomach contents out the tube. In addition, the pump and gravity methods use delivery sets which can be connected to the tube for hours to deliver continuous enteral nutrition while the patient sleeps. Disconnection of the delivery set is a common problem and bulky pinch clamps are often used because the flip caps fail so often.
Feeding tubes usually protrude from the body about 6 to 10 inches and are sometimes left in place up to a year or longer since they are manufactured from inert, biocompatible silicone or polyurethane. Feeding can take place up to three to six times a day.
Many of the enteral delivery sets have rigid plastic connectors with gripping barbs or steps which tend to destroy or ruin the various attempts at check valves used in feeding tubes. U.S. Pat. No. 4,944,732 describes one such device but this is limited to a low profile Gastro-Port from Sandoz Nutrition Corp. Recently Wilson-Cook Medical, Inc. has commercially introduced the Passport low profile gastrostomy device which functions similar to the Gastro-Port, but has a circular valve.
The circular valve structure of the Wilson-Cook Passport is described in detail along with relevant prior art in U.S. Pat. No. 5,718,691 to Russo and U.S. Pat. No. 5,716,347 to Gibbs et. al. The Gibbs et. al. U.S. Pat. No. 5,716,347 utilizes the circular valve structure of U.S. Pat. No. 5,718,691 to Russo. The circular valve to Russo uses a structure similar to the present invention. However, the Russo circular valve has a rigid outer wall portion which applies direct inward compressive force on the inner slit diaphragm. While the circular valve of Russo has proven to be an excellent clinical device, this direct compressive force sometimes can result in misalignment or mismatch of the valve slit opening permitting slight backflow leakage out the valve, especially when barbed connectors are repeatedly used. In addition, the Russo valve requires a separate retainer cap which leaves an internal crevice, joint, or seam between the cap and the circular valve, which can accumulate enteral formula which could prematurely clog the entrance way to the valve if it is not flushed according to instructions. The present invention is considered to be an improvement over the Russo circular valve in that the valve of the present invention eliminates the slight backflow, reduces the need for meticulous flushing and nursing care and extends the indwelling longevity of the device.
Other valve structures for catheter ports are shown in the prior art in the Bodai U.S. Pat. No. 4,351,328 and the hemostasis valve of Guest U.S. Pat. No. 5,000,745 and the valve of Suzuki U.S. Pat. No. 4,673,393. These devices are adequate for their intended short term use, but would not prove to be reliable over long term or repeated connection and disconnection use.
Other general medical art valves include U.S. Pat. Nos. 3,853,127 to Spademan; 4,430,081 to Timmermans; 5,114,408 to Fleishhaker et. al.; 5,125,903 to McLaughlin et. al.; and 5,261,885 to Lui.
U.S. Pat. No. 5,279,571 to Larkin discloses a self-sealing valve with a non-interference fit within its rigid housing which is contrary to the present invention. U.S. Pat. No. 5,167,637 to Okada et. al. is also a short term hemostatic valve, and U.S. Pat. No. 5,336,203 to Goldhardt is also a low profile gastrostomy device with a valve included as part of its structure.
All of the above devices are designed for either hemostatic access sites, parenteral injection sites, or low profile gastrostomy ports with limitations. None provide a universal, one size fits all type catheter adapter which can directly connect to a wide variety of catheters and can accept all delivery sets whether pump or gravity as well as directly connect to a bolus 60 cc syringe.
The present invention is directed to a low cost closed system adapter for long term use with indwelling catheters with advantages over the previously described devices.